package com.zhxh.nzpos.utils;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.os.Environment;

public class DBUtil {

	private final static String DB_NAME = "sell.sqlite";// 数据库名
	private final static int VERSION = 1;// 版本号
	public static final String PACKAGE_NAME = "com.zhxh.nzpos";
	public static final String DB_PATH = "/data"
			+ Environment.getDataDirectory().getAbsolutePath() + "/"
			+ PACKAGE_NAME +"/databases";// 在手机里存放数据库的位置
	
	public static void initDataBase(Context myContext) {
		if (!checkDataBase()) {
			try {
				copyDataBase(myContext);
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	
	// 搜检数据库是否有效
	private static boolean checkDataBase() {
		SQLiteDatabase checkDB = null;
		String myPath = DB_PATH + "/" + DB_NAME;
		try {
			checkDB = SQLiteDatabase.openDatabase(myPath, null,
					SQLiteDatabase.OPEN_READONLY);
		} catch (SQLiteException e) {
			// database does""t exist yet.
		}
		if (checkDB != null) {
			checkDB.close();
			System.out.println("");
		} else {
			File folder = new File(DB_PATH);
			if (!folder.exists()) {
				folder.mkdirs();
			}
			File file = new File(myPath);
			try {
				file.createNewFile();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
		return checkDB != null ? true : false;
	}
	
	 private static void copyDataBase(Context myContext) throws IOException{
		 
		//Open your local db as the input stream
		InputStream myInput = myContext.getAssets().open(DB_NAME);
		 
		// Path to the just created empty db
		String outFileName = DB_PATH + "/" + DB_NAME;
		 
		//Open the empty db as the output stream
		OutputStream myOutput = new FileOutputStream(outFileName);
		 
		//transfer bytes from the inputfile to the outputfile
		byte[] buffer = new byte[1024];
		int length;
		while ((length = myInput.read(buffer))>0){
		myOutput.write(buffer, 0, length);
		}
		 
		//Close the streams
		myOutput.flush();
		myOutput.close();
		myInput.close();
		 
		}
}
